Low
S.39 on Vaillant ecoTEC plus System

Your boiler is temporarily pausing because the external switch that monitors your underfloor heating system is currently signaling that the circuit is in the off position.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description

Underfloor heating contact open

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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